All elements of mass greater than Iron are either a) Big Bang remmnants, b) created by mad scientists with nuclear acclearators. Fusion in stars stops at Iron.
No. You're correct that, because of the curve of nuclear binding energy, you can't produce anything more massive than iron through fusion. But that doesn't mean heavier elements than iron come from the Big Bang. In fact, atoms heavier than carbon cannot be produced through Big Bang nucleosynthesis; H through C is all that's around when the first generation of stars form. Elements heavier than iron are produced in high-energy nuclear reactions that occur during supernovae. This is standard contemporary astrophysics, from any current textbook.
You are a little too quick to dismiss the possibility of potential practical applications down the road.
I don't dismiss it; that is, I don't say it's impossible. What I say that I don't believe it'll happen. Put another way: it's possible, but I really, really doubt it.
"Recreating something that existed at the time of the formation of the universe" in itself may not have any applications, but in the process we gain a better understanding of the strong interaction (or strong force), which is responsible for holding the atomic nucleus together, and for processes such as nuclear fusion, which powers the sun, and some nuclear fission reactions.
Hmmm. Can you elaborate on how an improved understanding of QCD at temperatures above 200 MeV is going to teach us much about fission or fusion, processes that occur at typical particle energies of 1-10 MeV. In the case of fission, or understanding the internals of heavy nuclei, my (perhaps wrong) understanding of the status of lattice gauge calculations was that issues of the quark-gluon coupling at those lower energies weren't where the uncertainties lie. Or is that incorrect?
The theory of the strong interaction, Quantum Chromodynamics, is the least well understood among all fundamental interactions.
No, gravity is the least well understood among all fundamental interactions. But it's definitely true that QCD is the least well understood part of the Standard Model.
To say that improving our knowledge of a fundamental force of nature through testing its predictions will not contribute to future advances is to ignore the history of science. People said similar things about electromagnetism just over a century ago.
As a general rule, I agree. In fact, I said exactly this in the first full paragraph of the post to which you just replied.
Recreating something that existed at the time of the formation of the universe is facinating and all, but , what are the practicle applications for this research?
Need it have a "practical application"?
How will it benifit mankind?
Well, that's a very different question.
I don't think this will have any practical value, per se. Absolutely zero. Oh, it's possible that down the road someone
much cleverer than I will come up with something. In fact, that's
the normal way in which major technological advances have occurred.
For instance, when Schottky began studying the quantum behavior of
transition metals, he wasn't interested in the tiniest bit in any
sort of practical application; he just wanted to understand the implications of quantum mechanics for electrons inside certain solids. If you had asked at
the time, "what's the practical benefit of this work?" the answer
would have been "zippo." And yet pretty much all of modern technology
is based upon the transisitor that was so discovered. That's the
way it's always been. Michael Faraday didn't really see any public
benefit to understanding electromagnetism, either. Pure research
has historically been without such obvious benefit.
But nevertheless, I don't want to suggest that that's the eventual
result here, because I don't believe it will be. I think that would
be disingenuous of me. I highly doubt that an improved understanding
of the history of the Universe from the Big Bang to the present will
ever produce any wonderful and amazing technological advance. To me,
the motivation is simply that understanding and knowledge --
especially of something like how the Universe got to be the way it is,
and why it works the way it does -- is inherently a good thing. It
has value by definition. Perhaps my least favorite thing about our
society is that we are trained to evaluate the worth of things in
terms of their economic value. Just like love, understanding has its
own value, in my mind -- bereft of any "practical" value.
Let me give you an example of what I mean. To the best of our ability
to tell, there's only one place where elements heavier than carbon
(such as nitrogen, oxygen, sodium, etc. etc.) can be formed in large
amounts -- and that's inside a star. Only elements as heavy as carbon
or lighter can be formed in the early universe; for heavier elements,
you need a star. Now, if you didn't already know this, stop and think
about it for a second. A huge chunk of you, perhaps all of you, was
inside a star at one time. It appears that you and I are star debris. And it gets even better. The way that large amounts of these elements, forged within a star, can get out of the
star is if the star supernovas -- dies at the end of its lifetime with a big boom. That big boom also serves to make very heavy elements --
such as uranium, for instance -- that cannot be made even in a star while it's burning away. There's uranium, and other similar very
heavy elements, on our planet. Do you see what I'm getting at? Much of the atoms that make all of us up, that make this planet up, were at
one time inside a star (or stars) that lived its life, supernovaed, and spewed out its stellar debris with heavy elements. Eventually, maybe a few hundred million years later, that stuff is part of our planet, part of our atmosphere, our water, part of you and me. We are all brothers and sisters; we all came from the same place, sorta.
Now, that knowledge will never make me any money. It will never
have any practical benefit in my life. And yet, I consider myself
immensely richer for knowing it.
GPL advocates would consider code which was written to be linked into a GPLed work to be undeniably a derived work.
Would they? After all, nVidia writes proprietary kernel modules for Linux and distributes them; but I haven't seen people threatening nVidia over GPL violations. However . . .
Distributing a kernel with such code linked inside would undoubtedly get someone a nastygram from the copyright holder demanding the source to the addition.
. ..this is the key, I think -- the fact that it was distributed with the OS (in this case, with AIX). The claim that that code (not the technology, but the code) is derivative of SysV doesn't seem so far fetched.
So my question is . ..say it's all valid, and at least as far as RCU is concerned, SCO has a valid complaint. It's only in a development kernel, and Linus pulls it. What ramifications are there for Linux? After all, in the USL/Novell vs. UC/BSD case, the BSD folks did have to chuck 8 files; but they still won the case. The principle damage to them was in the lost time, and the FUD. Right now, those seem like the biggest threats to Linux here as well. Or am I missing something?
OTOH, if it is all valid, then SCO's claim of contract violation against IBM is valid, if small. So there may be significant consequences for IBM.
Was out for a while, and am only able to respond to this now . . .
I was going to ask you how you knew this -- how you knew what the contract said -- but I see your post about this elsewhere in the subthread, with the link to SCOSource. I would mod that up if I were still allowed to (having posted in this discussion).
Anything more I'll say over there, out of an effort to keep this straight in my head!
Your understanding of the USL/BSD case is faulty. While the court did find that BSD included a small amount of code from AT&T, they also found that AT&T took much more than that from BSD.
Hi. Thanks. I don't think that contradicts what I said, though. The fact that the court found the SysV code infringing doesn't contradict the court finding the BSD code infringing. I certainly wasn't suggesting that UC/BSD "lost the case" in any way; merely that it is possible for copyright infringement against the SysV code to occur.
Your understanding of derivative works is similarly faulty. While it's true that the issue of what is a derivative work in software has never been litigated, it is not true that the owner of the original work owns the copyright to the derivative work. When a company, like IBM, buys the right to make derivative works, they own the copyright on the derivative work. Disney bought the rights to make films from A.A. Milne's Winnie the Pooh. The Milne heirs do not own the rights to those films,
Disney does.
You're right, and I misspoke. What I should have said is that U.S. Copyright Law is clear on the fact that the creation of derivative works of things which are still under copyright is the province of the copyright holder. To create derivative works, one must obtain the permission of the original copyright holder, and to do otherwise is a copyright violation. In the example you use above, Disney's Pooh films were not a violation if permission to make those films was granted by the holder of the copyrights to the Pooh stories (Milne or a publisher or whoever).
Thanks for catching me on this; it makes me feel a lot better, because the difference is obviously pretty significant here. Obviously, IBM had permission to create a derivative work!
Okay. So if USL lost, then the precedence has already been set -- USL didn't have rights to derivative works as ruled by the courts, so neither does SCO, because SCO has the same rights USL had, presumably. The OSI position paper covers this.
Well, my understanding of the particulars of the USL/Novell v. UC/BSD case isn't as good as it might be; but my understanding is that where Novell and USL were shot down was in their claims of trade secret infringement. Some copyright violation was found, requiring a small amount of code change within BSD to be necessary.
In other words, I thought the message of that case was that the SysV code was effectively unencumbered with trade secret issues; but copyrights could still be violated. Is that not correct?
If it is correct, then things get slightly more worrisome. In the case that we're discussing -- the Read-Copy Update issue -- I have no idea what argument would let SCO claim they have automatic rights to the technology. But copyright law is quite explicit about who owns the copyright to derivative works of some original work -- namely, the holder of the copyright to the original work. Taken literally, that would seem to imply that SCO does have some rights over AIX and its contents. Of course, my confusion over the details of the outcome of the Novell/USL v. UC/BSD case notwithstanding, I don't think the applicability of these rules about derivative works to software source code has been clearly considered by the courts. Completely independent of the outcome, this case may end up having a lot of impact about what software copyright really means.
And RCU is clearly a technology that Sequent designed for DYNIX/ptx. Sequent, as the link to RCU states, is now owned by IBM, so I suppose they'd have clear rights to this, no problem. RCU is also notoriously absent from SCO's product, so how they can claim ownership of the technology is beyond me.
OK, I could be completely wrong here. Lord knows trying to figure out what's in these people's minds is hard. But here's what I think is going on, and why they make such a claim. I preface this by saying that it was other posters here, in yesterday's SCO-related articles, that first made this point to me.
First, check out
this C|Net article, containing a brief interview with the CEO of SCO. In particular, note this quote:
Where people get a little confused is when they think of SCO Unix
as just the Unix that runs the cash register at McDonalds. We think
of this as a tree. We have the tree trunk, with Unix System 5
running right down the middle of the trunk. That is our core
ownership position on Unix.
Off the tree trunk, you have a number of branches, and these are
the various flavors of Unix. HP-UX, IBM's AIX, Sun Solaris, Fujitsu,
NEC--there are a number of flavors out there. SCO has a couple of
flavors, too, called OpenServer and UnixWare. But don't confuse the
branches with the trunk. The System 5 source code, that is really
the area that gives us incredible rights, because it includes
the control rights on the derivative works that branch off from
that trunk.
I added the boldface to that last clause for emphasis.
Similarly, Chris Sontag, SCO's Senior Vice President of the Operating Systems Division,
said the following in this Byte magazine article:
We believe that UNIX System V provided the basic building blocks for all subsequent computer operating systems, and that they all tend to be derived from UNIX System V (and therefore are claimed as SCO's intellectual property).
The point is that I think they feel they have some sort of rights over the additional code and technologies that licensees add to the System V code they license from SCO in the process of creating their particular product. IBM bought Sequent, acquiring Sequent's RCU technology. IBM added that technology to AIX. Apparently, in SCO's mind, that gives SCO some degree of rights over that technology, because it's now part of AIX, and AIX is a derivative work of SCO's System V code, and SCO believes they have some amount of rights over all derivative works. And therefore, claims SCO, adding it to Linux violated SCO's rights.
This seems like what they're saying. It also seems completely nuts -- unless IBM's license for SysV code for AIX gives the rights for technologies they come up with and add to AIX back to the owner of the System V codebase. I can't imagine that being true, though.
Another read on this is that it looks even more than it did before like an attempt to re-try the Unix Systems Labs vs. BSD case.
I submitted this a few hours ago (always a bridesmaid, *snif*), along with two links not in the story above. One was to the NY Times story
about it. The other was to
this story which just came out at Wired . ..a brief interview with Linus about his efforts to stand apart from political issues surrounding Open Source, which refers to the
discussion here on Slashdot
about his opinions on incorporating DRM into the Linux kernel (among other things).
OK, this will probably cost me karma, but I gotta say it: I can't help but wonder if the last question, asked by someone who wished to remain anonymous, was posed anonymously to avoid admitting publicly to owning (and choosing to listen to) John Denver's Greatest Hits.
1. You're asking a legal question. You want legal advice. Ask Slashdot is a lousy place to get your legal advice. I wouldn't trust anything anyone here (including what I write below) says about this as a reliable indicator that you wouldn't get sued.
2. You would be charging for the content, even if you weren't doing so explicitly. That charge is folded into the cost of the drinks/coffee/muffins/whatever that you'd be serving. After all, you're not showing the content out of the kindness of your heart; you're showing it in hopes that it'll draw people into your shop.
You might think that if you're not kicking people out for not buying stuff, you're not charging; but in at least one circumstance, the U.S. courts have disagreed. In the U.S., business establishments that play background music (e.g. those Linkin Park/Lynyrd Skynyrd/Leonard Cohen songs you hear in the background when you go to your favorite club/bar/coffeehouse) are required to
pay money for doing so to ASCAP. Most people don't realize this, but it's true. This is not incredibly aggressively enforced, but it is enforced. My favorite undergrad bar was shut down permanently because it wasn't making regular payments to ASCAP for the taped music it played before bands and in-between sets, and couldn't afford the fines and lump-sum payment once the court found against them.
Now, the music biz has all kinds of weird licensing restrictions and legislation, and I have no idea whether or not playing video content in your shop would be similar to playing music in your shop, in terms of your licensing obligations
(once again, you need to talk to a real lawyer). But the fact that it is this way for music should make you look into this in more detail.
I played this game a ton when it first came out, something like 23 years ago, when it was Eon Productions that made it. It was fantastic. The variety of alien powers and ways in which they could interact made every match different and interesting.
Then, Eon Productions released an expansion set with more alien powers. That was OK, although some of the new powers seemed poorly thought out -- too weak, or (worse) way too strong. Then a second expansion set came out, and it was more of the same. Then a third set came out, containing the "flare cards," whose introduction of random powers at random times into the game destroyed any ability to develop and pursue a strategy. You could think up some clever way to maximize the usefulness of your power against the other players' in this particular game; but the flare cards meant that any power could come up at any time.
So don't play with the expansion sets? Hard, if you wanted to play with other people. And when Mayfair Games bought the rights to distribute CE, they folded all that stuff into the game itself -- so people who came to the game at that point had those new unbalancing powers and the flare cards as part of the base game; convincing people you might want to play with that "we'd be better off ignoring those" didn't work so well. And so the game was still mildly entertaining, but nothing like it was when it first came out.
I also listened in on the conference call; wanted to ask a question but didn't get a chance.
The parent poster already said this, but given the size of the post and the fact that it was being written during the call (and thus somewhat stream-of-consciousness in style), I wanted to emphasize one thing: SCO's CEO McBride stated during the call that they're confident that they do own the copyrights (which would mean Novell's claim of ownership in the press release must therefore be false, if SCO were correct).
Heh, I submitted this seemingly seconds before it was posted by Michael.
The press release link at Novell in the story appears to have been replaced with a blank page, at least for now.
This story at the Inquirer includes a copy of the letter that Novell's CEO sent to SCO's CEO Darl McBride. Good stuff.
Would this even be possible? My understanding was that in order to file suit, you have to demonstrate that you have standing -- that is, that you personally are affected in such a way that it makes sense for you to be bringing the suit. Wouldn't all these zillions of worker bees be forced to show they have standing (with most of them then failing to do so)?
Or am I missing something here? (quite possible -- as usual around here, IANAL)
Do you know how to read? Try reading the GPL. It requires any derivative works to also be GPL. That's a restriction, because it means you can never make software that is available for sale from anything that has been opened as GPL.
Uh, actually, it looks like you need to read the GPL yourself.
You absolutely can `make software that is available for sale from software that's been released under the GPL.' Red Hat, SuSE, etc., do it every single day, when they patch the Linux kernel and release their versions. You are not restricted from selling software that you've come up with by modifying stuff previously released under the GPL. The restriction is simply that whether you sell it or give it away, it too must be released under the GPL.
This is a very simplistic response, but it'll have to do:
The situation you describe (two isolated/bare quarks or antiquarks, separated by a vast distance) can't really occur in the theory. It takes energy to separate the quarks/antiquarks in a subatomic particle; and because of the force getting stronger as the distance increases, it keeps taking more and more energy. As you separate the quarks, you're raising the potential energy of the system, just as if you were rolling a ball up the side of a bowl. Eventually you've put enough energy into the system to allow the creation of new particles -- specifically, a quark-antiquark pair, each member of which binds to the two quarks you're trying to separate, giving you two subatomic particles where before you had one (and still no bare quarks).
This phenomenon (among others) occurs all the time in particle accelerators in which hadrons (that is, particles made up of quarks and antiquarks) are collided, such as the Tevatron at Fermilab or the Large Hadron Collider at CERN. Protons at high energies collide with protons or antiprotons, and the input energies of the colliding particles provide the energy necessary for particle creation in the process described above.
The combination was not the surprise, but the missing mass is, which suggests that the theoretical calculation of the binding force is incorrect (though such calculation is often an approximation themself) This usually signals that some aspect of the theory on the force is wrong or that their is yet another particle that was undetected, thus robbing some mass away. (Neutrino was 'discovered' this way)
Well, sorta. In the case of the neutrino, conservation of energy and momentum gave you a solid expectation against which you could notice the missing momentum. So the analogy is only relevant if you expect the theoretical calculation of this resonance's mass to be accurate in the first place. But such calculations are notoriously difficult to do, and few people who haven't hitched their careers to doing lattice QCD calculations believe that we really know how to do them well. The "benefit" of this discrepancy is, as you partly suggest, that it will hopefully improve the (typically numerical) models people use to do these kinds of calculations.
> He just now realized this? Why didn't he leave USENET 5 years ago?
Uh, if you'd actually read the post, you'd see that it was made 10 years ago. He was describing the evolution of Usenet content from the early 1980s to the early 1990s.
Dammit, thats so unfair. The government should force companies to sell their property to other companies at cheap rates. Why should companies benefit from investing in infrastructure? The big companies should just buy lines for other small companies to use for free because they have more money. Damn capitalist pigs.
Seriously? Anyone here believe in private property? I mean, would it be fair to for the government to force you to fix your relatives computers whenever they wanted because you have more knowledge then them? Or you to lone your car to the homeless guy down the street because you have more resources then them? I mean, if you want to, then sure. But to force you??
Except, as has been noted umpteen times, the construction of that infrastructure occurred under an explicit government-endorsed monopoly on the creation of such an infrastructure, and furthermore was financially subsidized by the government.
Several people here have noted (correctly) that parody is considered "fair use"; there's a significant body of case law on this, and people here have provided links to some of that.
It's worth emphasizing, however, that fair use is a defense that you use in court, rather than a principle you cite to avoid court. As Brad Templeton notes in his
10 Big Myths about copyright explained,
This is not a
loophole; you can't just take a non-parody and claim it is one on a technicality. The way "fair use" works is you get sued for copyright infringement, and you admit you did infringe, but that your infringement was a fair use. A subjective judgment on, among other things, your goals, is then made.
So regardless of how solid your position may seem, if they're really coming after you, then you really do need a lawyer.
Have they realized yet that they could respond to the Scientology barratry as gracefully and fairly as Google did?
I hope their stance has changed, and I simply haven't heard about it.
I have become so disappointed in the
Internet Archive, and the people associated with it who claim to be motivated by a dedication to intellectual freedom.
First of all, I'd like to say that what you wrote was quite well-
written and informative, most especially for what one normally
sees on Slashdot.
Thanks. As a cosmologist, cosmology discussions are the one
subject on Slashdot that I feel comfortable weighing in on. So I
usually save my comments for such topics; I feel on more firm ground.
The first point you made was about whether it's correct to view the
BB as an explosion. There are two confounded issues here. The first is
something like "what size was the universe at the inception", or
"letting time go backward, what's the smallest the universe
gets?". The second is whether or not the metaphor of explosion is
correct to describe it.
The first issue was about "the size of the universe at inception",
whatever that may mean. I don't think it really makes sense to
differentiate between finite and zero size.
It makes sense to differentiate between them because they're two
physically different situations.
I mean, look, at some
timescale, and some temperature, all physical law will break
down. Then what can we say? Let time run backward. Why should it
continue to shrink to a 0-D point? Why not stop at 10^{whatever} m?
I'm not quite sure what you're saying here. If you're saying that
we don't know that we can extrapolate backwards all the way to
the singularity, I agree completely. We have experimental data that
only goes back to a temperature of about a TeV. Furthermore, the
Friedmann Equations are derived by presuming General Relativity to
hold; but we don't expect it to hold for arbitrarily high densities
and energies. We don't have a quantum theory of gravity, we don't
know what the laws of physics will be like at arbitrarily high
energies; so we don't know whether we can extrapolate all the way
back to a singularity. Absolutely true.
But regardless of whether the Big Bang model describes the evolution
of the universe from initial conditions of a singularity or from
initial conditions of some hot, dense state at some finite time, the
expansion of the universe is not well-portrayed by imagining the
matter content of the universe flying apart in space. The expansion
of the universe is not matter moving out from a single location
in space, as if an explosion happened there. Instead, it's an expansion
of space itself. This is not merely a semantic difference; these
two descriptions make significantly different (and observable) predictions.
Of particular interest is that the Cosmological Principle -- one of the
two postulates upon which the Big Bang model is based (the other being
that GR provides an accurate description of the universe) -- is
violated in a universe where things started with a big explosion
at a single location in space that flung all matter outward. Such a
picture violates one of the two postulates upon which the Big Bang
model is built.
To the second issue, I think we must both agree that the question
of a metaphor being "right" or "wrong" is tricky, and I may even go so
far as to say the question is ill-posed. For example, you say
> The point is that the idea of some sort of really tiny
> pellet of supercompressed matter exploding outward implies
> that space already exists
Here I disagree. As I said in my original post, "the universe started
expanding", not "the stuff in the universe started moving outward". In
fact, I think if I actually say that spacetime exploded, I really
think that this is an accurate metaphor for what happened. Again, as I
said, we can argue for infinite time whether or not this metaphor is
good pedagogically, with no real end in sight. But, in my mind, when I
think of nothing moving, then all of the sudden a bunch of shit
moving, I'd call that an explosion. Never mind whether or not it's
some matter, or spacetime itself.
But the problem I have with what you're saying is that "moving" is
a dangerous term to use. Not necessarily wrong, but potentially
misleading. According to Merriam-Webster's, "moving" would
imply a change in location, and I'm arguing that that's a bad way to
think of the expansion. In the absence of so-called "peculiar
velocities," driven by inhomogeneities in the mass distribution,
the expansion is solely because space is expanding; everything in
the universe stays at exactly the same location it's ever been, while
the space between expands.
Which brings me to the question, as you put it, of "whether or not
this metaphor is good pedagogically." I don't think we need to
argue this for infinite time, because we have the data at hand: look
at the questions many people have asked in this thread. Discounting
all the crazy "this proves/disproves the Bible/Koran/Necronomicon/
what-I-read-on-the-Quisp-box" b.s., most of the misconceptions I've
read in this thread have had their origins in people's belief that
the Big Bang is well-described by an explosion that took place at
a particular location in space, flinging everything outward. When
you say "explosion," that's what people think of, and it's the wrong
thing to think of.
You say that "explosion" implies space already existing, but you
read too much into it. I mean, look, the theory is called the "Big
Bang". Is that because we're supposed to think that there was a really
loud noise when it happened?
The model has that name because Fred Hoyle, one of the originators
of the Steady State model that was still viable back then, wanted to
give it a derisive name, and the name stuck. It wasn't given that
name for its pedagogical utility.
The second major point you raised with which I disagree is that
there is no debate on the validity of the BB model. I could not
disagree more. As you said:
> If you can show me some evidence for such a serious
> debate within the community (journal cites, for
> instance), I'd like to see it. That's not to say that
> the cosmological community believes that there's
> nothing left to figure out; there's a lot to figure
> out. And that's not to say that the cosmological
> community believes, as a whole, that the Big Bang
> model will survive as it is without modification or
> supplement. But the consensus of the community is
> that whatever the correct description of the
> evolution of the Universe is, its evolution from
> a time when the age of the universe was about
> 10^-24 of what it is now and the average temperature
> of stuff in the univese was about a trillion degrees
> Kelvin, up to the present day, will look a lot like
> the Relativistic Hot Big Bang model.
There actually are quite a few references on this, but a good survey
of an alternate theory is here [ams.org]. If you don't have access to
the AMS site, the reference is
Daignault and Sangalli, "Einstein's Static Universe: An Idea whose
Time has Come?", Notices of the American Mathematical Socity, (48),
no. 1, pp. 1--16.
I grant you that this is a mathematics journal as opposed to a physics
one, but this is as legitimate a journal as there is in the
mathematics community.
The mathematics community is not the cosmology community.
Notice the references in the paper to other
papers on the topic in Astro. J. and Proceedings of the Nat'l Academy
of Sciences. These are big-league journals that are publishing this
stuff, and this is clearly a respected alternate theory.
Now, to be fair, I don't necessarily buy the alternate arguments and I
am somewhat partial to Big Bang-like theories myself. But that being
said, there most certainly is a debate going on in the community, as
the above article shows.
No.
If you wish to make the statement that there are physicists and
mathematicians who are considering alternative cosmological models,
that's fine. I have no problem with that. If you wish to make
the statement that they're publishing articles that occur in
peer-reviewed journals, that's OK too. But no
such debate is taking place within the cosmology community.
To be blunt, the
people, the reference, and the journal that you give above are
not part of that community. I could probably name 150 cosmologists
and extragalactic astrophysicists off the top of my head; I'd bet
hard cash that none of them have ever published in Notices of
the AMS. I don't mean that as a slam against the publication,
I promise; I merely mean to indicate that it's not a cosmology
journal.
In the last decade, I've probably been to 20 or so major conferences
or workshops in cosmology (AAS meetings, Texas/PASCOS, Moriond
meetings, NATO ASIs, workshops at the Aspen Center for Physics,
various topical meetings on structure formation, etc. etc.), in a
variety of countries, and I can't remember a single time I saw
significant attention placed upon alternative cosmological models. In
fact, the only time I've seen any attention upon alternative
models was in a poorly attended session on the last day of a AAS
meeting in Washington, D.C. in January of (I think) 1994. To the
extent that people are debating the validity of the Big Bang model,
that debate is taking place outside the cosmology community.
On the third point, you did in fact correct a mistake I made,
but I would like to comment upon this further. I did say that
"most cosmologists would say that the universe is closed", which
I think, upon further reflection, is not quite accurate.
The topic is quite debatable.
No, not really. In the community of practicing cosmologists,
cosmologists who'd say they think the universe is closed are
hard to find. It's contradicted by present data.
On the other hand, I would not go so far as you:
> This would be correct if the data suggested that the
> topology/geometry of the Universe were that it were
> closed. That's not what the data say, and so that's
> not what the community believes.
Where I was too strong in my statement in one direction, I
believe that you have overstated in the other direction.
This is another topic which is even more debated than the
validity of the BB itself.
Not within the community. There is, at present, no data that
argues for a closed universe. Closed universe models were
taken seriously by the community at a time in the past, but
aren't really anymore; they're ruled out by the observational
data. Instead, the best data that we have argues for a flat
universe.
The most compelling data in this regard comes from observations of the
cosmic microwave background radiation (CMBR). The location of the
first Doppler peak in the angular power spectrum of cosmic microwave
background fluctuations sits at exactly the harmonic/wavenumber
it should if the universe is flat. This is a simple and powerful
geometric test: the size of the physical length scale of those largest
perturbations is calculable by simple physics; the distance to the
surface of last scattering is determined by the difference between the
CMBR temperature now (observed) and the temperature at the surface of
last scattering (specified precisely by atomic physics). In other
words, we know the size of our measuring rod, and we know the distance
to that rod; the angle it subtends upon the sky is therefore
determined entirely by the geometry of space. The BoomerANG
observations of several years ago,
as well as other groups conducting independent observations, argue quite convincingly that space is flat back to a
redshift of 1300 or so.
In fact, if the CMBR data did indicate a closed universe,
then that would mean trouble for cosmology, since simulations of
structure formation in closed universes produce large-scale structure
that both qualitatively and quantitatively (e.g. comparing the mass
two-point and higher-order correlation functions, galaxy cluster
number counts and their evolution, etc.) looks nothing at all like
the universe in which we live. Instead, the models which are viable
are open universe models, and flat universe models with a nonzero
cosmological constant (typically, Omega_matter ~ 0.25,
Omega_lambda ~ 0.75). Since the CMBR argues for a flat universe,
while a variety of other observations indicate just those values
for Omega_matter (galaxy cluster mass-to-light ratios, galaxy
cluster baryon fractions, lack of evolution in the cluster temperature
function) and Omega_lambda (esp. the high-redshift
Hubble diagram using Type Ia supernovae as standard candles),
the entire thing hangs together pretty well.
In fact, although I have heard arguments for an open topology,
I've never heard a physicist express what you did with that much
confidence.
Then I would bet that you haven't been going to that many conferences
in cosmology or extragalactic astrophysics, or haven't been keeping
current in the literature (the Astrophysical Journal,
the Monthly Notices of the Royal Astronomical Society,
Astronomy and Astrophysics, and occasionally Nature
for big results, are the main journals of the field).
For example, I saw a talk by Frank Tipler a few years back in which he
argued both sides of the coin.
Frank Tipler is not a good source to quote on this stuff.
Also, I believe the cover story of the New Scientist (for whatever
that's worth) was about this very issue. I do not think that there is
a real concensus on this issue either. Sorry about the lack of
explicit references here, but there's a lot of it out there, you
should be able to find it.
I'm familiar with the literature on this topic. It just doesn't agree with what you're saying.
That doesn't mean that there aren't papers suggesting it -- merely that those papers aren't taken seriously by the community at large, because they simply aren't supported by the data.
Slashdot Mirror
All elements of mass greater than Iron are either a) Big Bang remmnants, b) created by mad scientists with nuclear acclearators. Fusion in stars stops at Iron.
No. You're correct that, because of the curve of nuclear binding energy, you can't produce anything more massive than iron through fusion. But that doesn't mean heavier elements than iron come from the Big Bang. In fact, atoms heavier than carbon cannot be produced through Big Bang nucleosynthesis; H through C is all that's around when the first generation of stars form. Elements heavier than iron are produced in high-energy nuclear reactions that occur during supernovae. This is standard contemporary astrophysics, from any current textbook.
For an overview of Big Bang Nucleosynthesis, see e.g. The Early Universe by Kolb and Turner, or Cosmological Physics by John Peacock. Pitched at a lower level, try Joe Silk's The Big Bang . For more general descriptions of nucleosynthesis in stars and supernovae, see e.g. Harwit's Astrophysical Concepts or Bowers and Deeming's Astrophysics, Vol. I: Stars .
You are a little too quick to dismiss the possibility of potential practical applications down the road.
I don't dismiss it; that is, I don't say it's impossible. What I say that I don't believe it'll happen. Put another way: it's possible, but I really, really doubt it.
"Recreating something that existed at the time of the formation of the universe" in itself may not have any applications, but in the process we gain a better understanding of the strong interaction (or strong force), which is responsible for holding the atomic nucleus together, and for processes such as nuclear fusion, which powers the sun, and some nuclear fission reactions.
Hmmm. Can you elaborate on how an improved understanding of QCD at temperatures above 200 MeV is going to teach us much about fission or fusion, processes that occur at typical particle energies of 1-10 MeV. In the case of fission, or understanding the internals of heavy nuclei, my (perhaps wrong) understanding of the status of lattice gauge calculations was that issues of the quark-gluon coupling at those lower energies weren't where the uncertainties lie. Or is that incorrect?
The theory of the strong interaction, Quantum Chromodynamics, is the least well understood among all fundamental interactions.
No, gravity is the least well understood among all fundamental interactions. But it's definitely true that QCD is the least well understood part of the Standard Model.
To say that improving our knowledge of a fundamental force of nature through testing its predictions will not contribute to future advances is to ignore the history of science. People said similar things about electromagnetism just over a century ago.
As a general rule, I agree. In fact, I said exactly this in the first full paragraph of the post to which you just replied.
Recreating something that existed at the time of the formation of the universe is facinating and all, but , what are the practicle applications for this research?
Need it have a "practical application"?
How will it benifit mankind?
Well, that's a very different question.
I don't think this will have any practical value, per se. Absolutely zero. Oh, it's possible that down the road someone much cleverer than I will come up with something. In fact, that's the normal way in which major technological advances have occurred. For instance, when Schottky began studying the quantum behavior of transition metals, he wasn't interested in the tiniest bit in any sort of practical application; he just wanted to understand the implications of quantum mechanics for electrons inside certain solids. If you had asked at the time, "what's the practical benefit of this work?" the answer would have been "zippo." And yet pretty much all of modern technology is based upon the transisitor that was so discovered. That's the way it's always been. Michael Faraday didn't really see any public benefit to understanding electromagnetism, either. Pure research has historically been without such obvious benefit.
But nevertheless, I don't want to suggest that that's the eventual result here, because I don't believe it will be. I think that would be disingenuous of me. I highly doubt that an improved understanding of the history of the Universe from the Big Bang to the present will ever produce any wonderful and amazing technological advance. To me, the motivation is simply that understanding and knowledge -- especially of something like how the Universe got to be the way it is, and why it works the way it does -- is inherently a good thing. It has value by definition. Perhaps my least favorite thing about our society is that we are trained to evaluate the worth of things in terms of their economic value. Just like love, understanding has its own value, in my mind -- bereft of any "practical" value.
Let me give you an example of what I mean. To the best of our ability to tell, there's only one place where elements heavier than carbon (such as nitrogen, oxygen, sodium, etc. etc.) can be formed in large amounts -- and that's inside a star. Only elements as heavy as carbon or lighter can be formed in the early universe; for heavier elements, you need a star. Now, if you didn't already know this, stop and think about it for a second. A huge chunk of you, perhaps all of you, was inside a star at one time. It appears that you and I are star debris. And it gets even better. The way that large amounts of these elements, forged within a star, can get out of the star is if the star supernovas -- dies at the end of its lifetime with a big boom. That big boom also serves to make very heavy elements -- such as uranium, for instance -- that cannot be made even in a star while it's burning away. There's uranium, and other similar very heavy elements, on our planet. Do you see what I'm getting at? Much of the atoms that make all of us up, that make this planet up, were at one time inside a star (or stars) that lived its life, supernovaed, and spewed out its stellar debris with heavy elements. Eventually, maybe a few hundred million years later, that stuff is part of our planet, part of our atmosphere, our water, part of you and me. We are all brothers and sisters; we all came from the same place, sorta.
Now, that knowledge will never make me any money. It will never have any practical benefit in my life. And yet, I consider myself immensely richer for knowing it.
Understanding has its own value.
GPL advocates would consider code which was written to be linked into a GPLed work to be undeniably a derived work.
Would they? After all, nVidia writes proprietary kernel modules for Linux and distributes them; but I haven't seen people threatening nVidia over GPL violations. However . . .
Distributing a kernel with such code linked inside would undoubtedly get someone a nastygram from the copyright holder demanding the source to the addition.
. . .this is the key, I think -- the fact that it was distributed with the OS (in this case, with AIX). The claim that that code (not the technology, but the code) is derivative of SysV doesn't seem so far fetched.
So my question is . . .say it's all valid, and at least as far as RCU is concerned, SCO has a valid complaint. It's only in a development kernel, and Linus pulls it. What ramifications are there for Linux? After all, in the USL/Novell vs. UC/BSD case, the BSD folks did have to chuck 8 files; but they still won the case. The principle damage to them was in the lost time, and the FUD. Right now, those seem like the biggest threats to Linux here as well. Or am I missing something?
OTOH, if it is all valid, then SCO's claim of contract violation against IBM is valid, if small. So there may be significant consequences for IBM.
Was out for a while, and am only able to respond to this now . . .
I was going to ask you how you knew this -- how you knew what the contract said -- but I see your post about this elsewhere in the subthread, with the link to SCOSource. I would mod that up if I were still allowed to (having posted in this discussion).
Anything more I'll say over there, out of an effort to keep this straight in my head!
Your understanding of the USL/BSD case is faulty. While the court did find that BSD included a small amount of code from AT&T, they also found that AT&T took much more than that from BSD.
Hi. Thanks. I don't think that contradicts what I said, though. The fact that the court found the SysV code infringing doesn't contradict the court finding the BSD code infringing. I certainly wasn't suggesting that UC/BSD "lost the case" in any way; merely that it is possible for copyright infringement against the SysV code to occur.
Your understanding of derivative works is similarly faulty. While it's true that the issue of what is a derivative work in software has never been litigated, it is not true that the owner of the original work owns the copyright to the derivative work. When a company, like IBM, buys the right to make derivative works, they own the copyright on the derivative work. Disney bought the rights to make films from A.A. Milne's Winnie the Pooh. The Milne heirs do not own the rights to those films, Disney does.
You're right, and I misspoke. What I should have said is that U.S. Copyright Law is clear on the fact that the creation of derivative works of things which are still under copyright is the province of the copyright holder. To create derivative works, one must obtain the permission of the original copyright holder, and to do otherwise is a copyright violation. In the example you use above, Disney's Pooh films were not a violation if permission to make those films was granted by the holder of the copyrights to the Pooh stories (Milne or a publisher or whoever).
Thanks for catching me on this; it makes me feel a lot better, because the difference is obviously pretty significant here. Obviously, IBM had permission to create a derivative work!
Okay. So if USL lost, then the precedence has already been set -- USL didn't have rights to derivative works as ruled by the courts, so neither does SCO, because SCO has the same rights USL had, presumably. The OSI position paper covers this.
Well, my understanding of the particulars of the USL/Novell v. UC/BSD case isn't as good as it might be; but my understanding is that where Novell and USL were shot down was in their claims of trade secret infringement. Some copyright violation was found, requiring a small amount of code change within BSD to be necessary. In other words, I thought the message of that case was that the SysV code was effectively unencumbered with trade secret issues; but copyrights could still be violated. Is that not correct?
If it is correct, then things get slightly more worrisome. In the case that we're discussing -- the Read-Copy Update issue -- I have no idea what argument would let SCO claim they have automatic rights to the technology. But copyright law is quite explicit about who owns the copyright to derivative works of some original work -- namely, the holder of the copyright to the original work. Taken literally, that would seem to imply that SCO does have some rights over AIX and its contents. Of course, my confusion over the details of the outcome of the Novell/USL v. UC/BSD case notwithstanding, I don't think the applicability of these rules about derivative works to software source code has been clearly considered by the courts. Completely independent of the outcome, this case may end up having a lot of impact about what software copyright really means.
They're always funnier when I explain 'em . . .
And RCU is clearly a technology that Sequent designed for DYNIX/ptx. Sequent, as the link to RCU states, is now owned by IBM, so I suppose they'd have clear rights to this, no problem. RCU is also notoriously absent from SCO's product, so how they can claim ownership of the technology is beyond me.
OK, I could be completely wrong here. Lord knows trying to figure out what's in these people's minds is hard. But here's what I think is going on, and why they make such a claim. I preface this by saying that it was other posters here, in yesterday's SCO-related articles, that first made this point to me. First, check out this C|Net article, containing a brief interview with the CEO of SCO. In particular, note this quote:
I added the boldface to that last clause for emphasis.
Similarly, Chris Sontag, SCO's Senior Vice President of the Operating Systems Division, said the following in this Byte magazine article:
The point is that I think they feel they have some sort of rights over the additional code and technologies that licensees add to the System V code they license from SCO in the process of creating their particular product. IBM bought Sequent, acquiring Sequent's RCU technology. IBM added that technology to AIX. Apparently, in SCO's mind, that gives SCO some degree of rights over that technology, because it's now part of AIX, and AIX is a derivative work of SCO's System V code, and SCO believes they have some amount of rights over all derivative works. And therefore, claims SCO, adding it to Linux violated SCO's rights.
This seems like what they're saying. It also seems completely nuts -- unless IBM's license for SysV code for AIX gives the rights for technologies they come up with and add to AIX back to the owner of the System V codebase. I can't imagine that being true, though.
Another read on this is that it looks even more than it did before like an attempt to re-try the Unix Systems Labs vs. BSD case.
I submitted this a few hours ago (always a bridesmaid, *snif*), along with two links not in the story above. One was to the NY Times story about it. The other was to this story which just came out at Wired . . .a brief interview with Linus about his efforts to stand apart from political issues surrounding Open Source, which refers to the
discussion here on Slashdot
about his opinions on incorporating DRM into the Linux kernel (among other things).
OK, this will probably cost me karma, but I gotta say it: I can't help but wonder if the last question, asked by someone who wished to remain anonymous, was posed anonymously to avoid admitting publicly to owning (and choosing to listen to) John Denver's Greatest Hits.
P.S. Volume 2???
1. You're asking a legal question. You want legal advice. Ask Slashdot is a lousy place to get your legal advice. I wouldn't trust anything anyone here (including what I write below) says about this as a reliable indicator that you wouldn't get sued.
2. You would be charging for the content, even if you weren't doing so explicitly. That charge is folded into the cost of the drinks/coffee/muffins/whatever that you'd be serving. After all, you're not showing the content out of the kindness of your heart; you're showing it in hopes that it'll draw people into your shop.
You might think that if you're not kicking people out for not buying stuff, you're not charging; but in at least one circumstance, the U.S. courts have disagreed. In the U.S., business establishments that play background music (e.g. those Linkin Park/Lynyrd Skynyrd/Leonard Cohen songs you hear in the background when you go to your favorite club/bar/coffeehouse) are required to pay money for doing so to ASCAP. Most people don't realize this, but it's true. This is not incredibly aggressively enforced, but it is enforced. My favorite undergrad bar was shut down permanently because it wasn't making regular payments to ASCAP for the taped music it played before bands and in-between sets, and couldn't afford the fines and lump-sum payment once the court found against them.
Now, the music biz has all kinds of weird licensing restrictions and legislation, and I have no idea whether or not playing video content in your shop would be similar to playing music in your shop, in terms of your licensing obligations (once again, you need to talk to a real lawyer). But the fact that it is this way for music should make you look into this in more detail.
I played this game a ton when it first came out, something like 23 years ago, when it was Eon Productions that made it. It was fantastic. The variety of alien powers and ways in which they could interact made every match different and interesting.
Then, Eon Productions released an expansion set with more alien powers. That was OK, although some of the new powers seemed poorly thought out -- too weak, or (worse) way too strong. Then a second expansion set came out, and it was more of the same. Then a third set came out, containing the "flare cards," whose introduction of random powers at random times into the game destroyed any ability to develop and pursue a strategy. You could think up some clever way to maximize the usefulness of your power against the other players' in this particular game; but the flare cards meant that any power could come up at any time.
So don't play with the expansion sets? Hard, if you wanted to play with other people. And when Mayfair Games bought the rights to distribute CE, they folded all that stuff into the game itself -- so people who came to the game at that point had those new unbalancing powers and the flare cards as part of the base game; convincing people you might want to play with that "we'd be better off ignoring those" didn't work so well. And so the game was still mildly entertaining, but nothing like it was when it first came out.
I also listened in on the conference call; wanted to ask a question but didn't get a chance.
The parent poster already said this, but given the size of the post and the fact that it was being written during the call (and thus somewhat stream-of-consciousness in style), I wanted to emphasize one thing: SCO's CEO McBride stated during the call that they're confident that they do own the copyrights (which would mean Novell's claim of ownership in the press release must therefore be false, if SCO were correct).
Heh, I submitted this seemingly seconds before it was posted by Michael.
The press release link at Novell in the story appears to have been replaced with a blank page, at least for now. This story at the Inquirer includes a copy of the letter that Novell's CEO sent to SCO's CEO Darl McBride. Good stuff.
Would this even be possible? My understanding was that in order to file suit, you have to demonstrate that you have standing -- that is, that you personally are affected in such a way that it makes sense for you to be bringing the suit. Wouldn't all these zillions of worker bees be forced to show they have standing (with most of them then failing to do so)? Or am I missing something here? (quite possible -- as usual around here, IANAL)
Do you know how to read? Try reading the GPL. It requires any derivative works to also be GPL. That's a restriction, because it means you can never make software that is available for sale from anything that has been opened as GPL.
Uh, actually, it looks like you need to read the GPL yourself.
You absolutely can `make software that is available for sale from software that's been released under the GPL.' Red Hat, SuSE, etc., do it every single day, when they patch the Linux kernel and release their versions. You are not restricted from selling software that you've come up with by modifying stuff previously released under the GPL. The restriction is simply that whether you sell it or give it away, it too must be released under the GPL.
But don't believe me; read the relevant part of the GPL FAQ.
HTH.
But what if you could somehow prevent the formation of the new particles?
There is no mechanism in the theory to do that.
This is a very simplistic response, but it'll have to do:
The situation you describe (two isolated/bare quarks or antiquarks, separated by a vast distance) can't really occur in the theory. It takes energy to separate the quarks/antiquarks in a subatomic particle; and because of the force getting stronger as the distance increases, it keeps taking more and more energy. As you separate the quarks, you're raising the potential energy of the system, just as if you were rolling a ball up the side of a bowl. Eventually you've put enough energy into the system to allow the creation of new particles -- specifically, a quark-antiquark pair, each member of which binds to the two quarks you're trying to separate, giving you two subatomic particles where before you had one (and still no bare quarks).
This phenomenon (among others) occurs all the time in particle accelerators in which hadrons (that is, particles made up of quarks and antiquarks) are collided, such as the Tevatron at Fermilab or the Large Hadron Collider at CERN. Protons at high energies collide with protons or antiprotons, and the input energies of the colliding particles provide the energy necessary for particle creation in the process described above.
The combination was not the surprise, but the missing mass is, which suggests that the theoretical calculation of the binding force is incorrect (though such calculation is often an approximation themself) This usually signals that some aspect of the theory on the force is wrong or that their is yet another particle that was undetected, thus robbing some mass away. (Neutrino was 'discovered' this way)
Well, sorta. In the case of the neutrino, conservation of energy and momentum gave you a solid expectation against which you could notice the missing momentum. So the analogy is only relevant if you expect the theoretical calculation of this resonance's mass to be accurate in the first place. But such calculations are notoriously difficult to do, and few people who haven't hitched their careers to doing lattice QCD calculations believe that we really know how to do them well. The "benefit" of this discrepancy is, as you partly suggest, that it will hopefully improve the (typically numerical) models people use to do these kinds of calculations.
> He just now realized this? Why didn't he leave USENET 5 years ago?
Uh, if you'd actually read the post, you'd see that it was made 10 years ago. He was describing the evolution of Usenet content from the early 1980s to the early 1990s.
HTH.
Seriously? Anyone here believe in private property? I mean, would it be fair to for the government to force you to fix your relatives computers whenever they wanted because you have more knowledge then them? Or you to lone your car to the homeless guy down the street because you have more resources then them? I mean, if you want to, then sure. But to force you??
Except, as has been noted umpteen times, the construction of that infrastructure occurred under an explicit government-endorsed monopoly on the creation of such an infrastructure, and furthermore was financially subsidized by the government.
Several people here have noted (correctly) that parody is considered "fair use"; there's a significant body of case law on this, and people here have provided links to some of that.
It's worth emphasizing, however, that fair use is a defense that you use in court, rather than a principle you cite to avoid court. As Brad Templeton notes in his 10 Big Myths about copyright explained,
So regardless of how solid your position may seem, if they're really coming after you, then you really do need a lawyer.Will the Internet Archive Bookmobile, from the same folks that bring us the Wayback Machine, contain materials critical of Scientology?
Have they realized yet that they could respond to the Scientology barratry as gracefully and fairly as Google did?
I hope their stance has changed, and I simply haven't heard about it. I have become so disappointed in the Internet Archive, and the people associated with it who claim to be motivated by a dedication to intellectual freedom.
Thanks. As a cosmologist, cosmology discussions are the one subject on Slashdot that I feel comfortable weighing in on. So I usually save my comments for such topics; I feel on more firm ground.
The first point you made was about whether it's correct to view the BB as an explosion. There are two confounded issues here. The first is something like "what size was the universe at the inception", or "letting time go backward, what's the smallest the universe gets?". The second is whether or not the metaphor of explosion is correct to describe it.
The first issue was about "the size of the universe at inception", whatever that may mean. I don't think it really makes sense to differentiate between finite and zero size.
It makes sense to differentiate between them because they're two physically different situations.
I mean, look, at some timescale, and some temperature, all physical law will break down. Then what can we say? Let time run backward. Why should it continue to shrink to a 0-D point? Why not stop at 10^{whatever} m?
I'm not quite sure what you're saying here. If you're saying that we don't know that we can extrapolate backwards all the way to the singularity, I agree completely. We have experimental data that only goes back to a temperature of about a TeV. Furthermore, the Friedmann Equations are derived by presuming General Relativity to hold; but we don't expect it to hold for arbitrarily high densities and energies. We don't have a quantum theory of gravity, we don't know what the laws of physics will be like at arbitrarily high energies; so we don't know whether we can extrapolate all the way back to a singularity. Absolutely true.
But regardless of whether the Big Bang model describes the evolution of the universe from initial conditions of a singularity or from initial conditions of some hot, dense state at some finite time, the expansion of the universe is not well-portrayed by imagining the matter content of the universe flying apart in space. The expansion of the universe is not matter moving out from a single location in space, as if an explosion happened there. Instead, it's an expansion of space itself. This is not merely a semantic difference; these two descriptions make significantly different (and observable) predictions. Of particular interest is that the Cosmological Principle -- one of the two postulates upon which the Big Bang model is based (the other being that GR provides an accurate description of the universe) -- is violated in a universe where things started with a big explosion at a single location in space that flung all matter outward. Such a picture violates one of the two postulates upon which the Big Bang model is built.
To the second issue, I think we must both agree that the question of a metaphor being "right" or "wrong" is tricky, and I may even go so far as to say the question is ill-posed. For example, you say
> The point is that the idea of some sort of really tiny
> pellet of supercompressed matter exploding outward implies
> that space already exists
Here I disagree. As I said in my original post, "the universe started expanding", not "the stuff in the universe started moving outward". In fact, I think if I actually say that spacetime exploded, I really think that this is an accurate metaphor for what happened. Again, as I said, we can argue for infinite time whether or not this metaphor is good pedagogically, with no real end in sight. But, in my mind, when I think of nothing moving, then all of the sudden a bunch of shit moving, I'd call that an explosion. Never mind whether or not it's some matter, or spacetime itself.
But the problem I have with what you're saying is that "moving" is a dangerous term to use. Not necessarily wrong, but potentially misleading. According to Merriam-Webster's, "moving" would imply a change in location, and I'm arguing that that's a bad way to think of the expansion. In the absence of so-called "peculiar velocities," driven by inhomogeneities in the mass distribution, the expansion is solely because space is expanding; everything in the universe stays at exactly the same location it's ever been, while the space between expands.
Which brings me to the question, as you put it, of "whether or not this metaphor is good pedagogically." I don't think we need to argue this for infinite time, because we have the data at hand: look at the questions many people have asked in this thread. Discounting all the crazy "this proves/disproves the Bible/Koran/Necronomicon/ what-I-read-on-the-Quisp-box" b.s., most of the misconceptions I've read in this thread have had their origins in people's belief that the Big Bang is well-described by an explosion that took place at a particular location in space, flinging everything outward. When you say "explosion," that's what people think of, and it's the wrong thing to think of.
You say that "explosion" implies space already existing, but you read too much into it. I mean, look, the theory is called the "Big Bang". Is that because we're supposed to think that there was a really loud noise when it happened?
The model has that name because Fred Hoyle, one of the originators of the Steady State model that was still viable back then, wanted to give it a derisive name, and the name stuck. It wasn't given that name for its pedagogical utility.
The second major point you raised with which I disagree is that there is no debate on the validity of the BB model. I could not disagree more. As you said:
> If you can show me some evidence for such a serious
> debate within the community (journal cites, for
> instance), I'd like to see it. That's not to say that
> the cosmological community believes that there's
> nothing left to figure out; there's a lot to figure
> out. And that's not to say that the cosmological
> community believes, as a whole, that the Big Bang
> model will survive as it is without modification or
> supplement. But the consensus of the community is
> that whatever the correct description of the
> evolution of the Universe is, its evolution from
> a time when the age of the universe was about
> 10^-24 of what it is now and the average temperature
> of stuff in the univese was about a trillion degrees
> Kelvin, up to the present day, will look a lot like
> the Relativistic Hot Big Bang model.
There actually are quite a few references on this, but a good survey of an alternate theory is here [ams.org]. If you don't have access to the AMS site, the reference is
Daignault and Sangalli, "Einstein's Static Universe: An Idea whose Time has Come?", Notices of the American Mathematical Socity, (48), no. 1, pp. 1--16.
I grant you that this is a mathematics journal as opposed to a physics one, but this is as legitimate a journal as there is in the mathematics community.
The mathematics community is not the cosmology community.
Notice the references in the paper to other papers on the topic in Astro. J. and Proceedings of the Nat'l Academy of Sciences. These are big-league journals that are publishing this stuff, and this is clearly a respected alternate theory.
Now, to be fair, I don't necessarily buy the alternate arguments and I am somewhat partial to Big Bang-like theories myself. But that being said, there most certainly is a debate going on in the community, as the above article shows.
No.
If you wish to make the statement that there are physicists and mathematicians who are considering alternative cosmological models, that's fine. I have no problem with that. If you wish to make the statement that they're publishing articles that occur in peer-reviewed journals, that's OK too. But no such debate is taking place within the cosmology community. To be blunt, the people, the reference, and the journal that you give above are not part of that community. I could probably name 150 cosmologists and extragalactic astrophysicists off the top of my head; I'd bet hard cash that none of them have ever published in Notices of the AMS. I don't mean that as a slam against the publication, I promise; I merely mean to indicate that it's not a cosmology journal.
In the last decade, I've probably been to 20 or so major conferences or workshops in cosmology (AAS meetings, Texas/PASCOS, Moriond meetings, NATO ASIs, workshops at the Aspen Center for Physics, various topical meetings on structure formation, etc. etc.), in a variety of countries, and I can't remember a single time I saw significant attention placed upon alternative cosmological models. In fact, the only time I've seen any attention upon alternative models was in a poorly attended session on the last day of a AAS meeting in Washington, D.C. in January of (I think) 1994. To the extent that people are debating the validity of the Big Bang model, that debate is taking place outside the cosmology community.
On the third point, you did in fact correct a mistake I made, but I would like to comment upon this further. I did say that "most cosmologists would say that the universe is closed", which I think, upon further reflection, is not quite accurate. The topic is quite debatable.
No, not really. In the community of practicing cosmologists, cosmologists who'd say they think the universe is closed are hard to find. It's contradicted by present data.
On the other hand, I would not go so far as you:
> This would be correct if the data suggested that the
> topology/geometry of the Universe were that it were
> closed. That's not what the data say, and so that's
> not what the community believes.
Where I was too strong in my statement in one direction, I believe that you have overstated in the other direction. This is another topic which is even more debated than the validity of the BB itself.
Not within the community. There is, at present, no data that argues for a closed universe. Closed universe models were taken seriously by the community at a time in the past, but aren't really anymore; they're ruled out by the observational data. Instead, the best data that we have argues for a flat universe.
The most compelling data in this regard comes from observations of the cosmic microwave background radiation (CMBR). The location of the first Doppler peak in the angular power spectrum of cosmic microwave background fluctuations sits at exactly the harmonic/wavenumber it should if the universe is flat. This is a simple and powerful geometric test: the size of the physical length scale of those largest perturbations is calculable by simple physics; the distance to the surface of last scattering is determined by the difference between the CMBR temperature now (observed) and the temperature at the surface of last scattering (specified precisely by atomic physics). In other words, we know the size of our measuring rod, and we know the distance to that rod; the angle it subtends upon the sky is therefore determined entirely by the geometry of space. The BoomerANG observations of several years ago, as well as other groups conducting independent observations, argue quite convincingly that space is flat back to a redshift of 1300 or so.
In fact, if the CMBR data did indicate a closed universe, then that would mean trouble for cosmology, since simulations of structure formation in closed universes produce large-scale structure that both qualitatively and quantitatively (e.g. comparing the mass two-point and higher-order correlation functions, galaxy cluster number counts and their evolution, etc.) looks nothing at all like the universe in which we live. Instead, the models which are viable are open universe models, and flat universe models with a nonzero cosmological constant (typically, Omega_matter ~ 0.25, Omega_lambda ~ 0.75). Since the CMBR argues for a flat universe, while a variety of other observations indicate just those values for Omega_matter (galaxy cluster mass-to-light ratios, galaxy cluster baryon fractions, lack of evolution in the cluster temperature function) and Omega_lambda (esp. the high-redshift Hubble diagram using Type Ia supernovae as standard candles), the entire thing hangs together pretty well.
In fact, although I have heard arguments for an open topology, I've never heard a physicist express what you did with that much confidence.
Then I would bet that you haven't been going to that many conferences in cosmology or extragalactic astrophysics, or haven't been keeping current in the literature (the Astrophysical Journal, the Monthly Notices of the Royal Astronomical Society, Astronomy and Astrophysics, and occasionally Nature for big results, are the main journals of the field).
For example, I saw a talk by Frank Tipler a few years back in which he argued both sides of the coin.
Frank Tipler is not a good source to quote on this stuff.
Also, I believe the cover story of the New Scientist (for whatever that's worth) was about this very issue. I do not think that there is a real concensus on this issue either. Sorry about the lack of explicit references here, but there's a lot of it out there, you should be able to find it.
I'm familiar with the literature on this topic. It just doesn't agree with what you're saying. That doesn't mean that there aren't papers suggesting it -- merely that those papers aren't taken seriously by the community at large, because they simply aren't supported by the data.